Metal Clay firing test results; Silver 1200F-1HR-OK, Silver 1475F-1HR-OK, Silver 1650F-2HR OK, Bronze 1525F-2HR-OK, Copper 1778F-30min-OK Fired in carbon and made sure not to open the kiln until completely cooled. Came out great with a slight haze, but they looked great. If you cool down too quickly they crack. But, if you put a little super glue over each one after firing they will look fine.